Oliver Dowden: There has been a lot of debate about whether the Government have a sufficient mandate not only to invoke article 50, but to exit the single market and enter the customs union. Many hon. Members might know that my involvement in that question did not begin when I was elected to this House in 2015. In the five years prior to then, I had the privilege of working in Downing Street. For me, the whole question of our membership of the EU is inextricably rooted in the conflict between control—principally of immigration and our own laws—on the one hand, and our membership of the single market on the other. In the decade that followed Tony Blair’s disastrous decision to allow the new eastern European members of the EU to gain full access to the labour market without transitional controls, net migration from the EU went from being roughly in balance to being in the hundreds of thousands every year.
The application of the single market to the field of labour went from facilitating the free movement of labour around countries of roughly equal development to a mechanism for mass economic migration. That, in turn, was compounded by the fact that the UK had not  only no transitional controls, but an open, English-speaking labour market that is much more conducive to migrants. Latterly, the eurozone crisis meant that while much of Europe stagnated, a mercifully free United Kingdom became a jobs-creation engine that sucked labour from stagnant continental countries.
All that led to a growing sense of a loss of control. These were huge changes about which the British people were never asked and to which they never consented. That was why Conservative manifestos repeatedly committed us to reducing migration to the tens of thousands, but our experience in government demonstrated that that could not be achieved.